Maltese Prime Minister Joseph Muscat on Sunday told the nation that he would resign next month, following pressure from angry citizens for the truth about the 2017 vehicle bombing that killed a journalist pursuing corruption.
On state TV, Muscat stated that "in the coming time we will launch a process to have a new prime minister".
While the PN MPs walked out, fake bank notes depicting the faces of Muscat, Konrad Mizzi and Keith Schembri were thrown into the air.
Muscat has announced he will quit as prime minister in January, after investigators alleged links between his administration and those who ordered the killing.
Parliament square has been barricaded by metal barriers.
Caruana Galizia's family said Muscat should have no further involvement in the case and petitioned a court to ensure he was excluded from any further access to the information.
In a short statement to the press on Monday, Muscat said he will "limit" himself to day-to-day operations of running the government, according to the Times of Malta.
Critics are angry with Muscat for sticking by Schembri, and for including him in security briefings on the investigation even after Fenech was identified as a suspect in the murder and as an associate of Schembri.
Again on Monday, protesters demanding Muscat's immediate departure demonstrated outside parliament on Monday, temporarily impeding lawmakers' exit from the building, while a group backing the outgoing PM was organising a counter-demonstration outside Labour party headquarters. A leading investigative journalist, she was part of the team who published "The Panama Papers", a global investigation detailing the shadowy efforts of the super-wealthy to hide money and power from tax authorities and others. "The case showed that Malta's institutions work and everyone is equal before the law", he said.
Caruana Galizia was the subject of lawsuits by some of her subjects, including in government.
"Malta is a part of Europe, this concerns us all", tweeted veteran Dutch Liberal MEP Sophie in 't Veld, who is leading the mission. There should not be impunity, no cover ups, and no culprit should escape trial ...
The European commission declined to comment on the investigation, but said it expected an "independent and through investigation and that the persons responsible for this crime must be brought to justice". He has been charged with participating in a criminal organization, complicity in the causing an explosion, and complicity in the murder of Caruana Galizia.
The investigation into her murder has rocked the Mediterranean island, reaching the highest echelons of government. The 38-year-old pleaded not guilty to that and other charges.
The decision comes after Muscat's former chief of staff, Keith Schembri, was released from jail late on Thursday.
Schembri and Mizzi both resigned last week and have denied wrongdoing.